JSONB containment (@>) operator in PostgreSQL - Step-by-Step Execution

Concept Flow - JSONB containment (@>) operator

Start with two JSONB values

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Check if left JSONB contains right JSONB

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Return TRUE

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End

The operator checks if the left JSONB value contains the right JSONB value and returns true or false accordingly.

Execution Sample

PostgreSQL

SELECT '{"a":1, "b":2}'::jsonb @> '{"a":1}'::jsonb AS contains;

This query checks if the JSONB on the left contains the JSONB on the right and returns true or false.

Execution Table

Step	Left JSONB	Right JSONB	Containment Check	Result
1	{"a":1, "b":2}	{"a":1}	Does left contain right?	TRUE
2	{"a":1, "b":2}	{"b":3}	Does left contain right?	FALSE
3	{"a":1, "b":{"c":3}}	{"b":{"c":3}}	Does left contain right?	TRUE
4	{"a":1, "b":{"c":3}}	{"b":{"c":4}}	Does left contain right?	FALSE

💡 All checks complete; results show if left JSONB contains right JSONB.

Variable Tracker

Variable	Start	Check 1	Check 2	Check 3	Check 4
Left JSONB	{"a":1, "b":2}	{"a":1, "b":2}	{"a":1, "b":2}	{"a":1, "b":{"c":3}}	{"a":1, "b":{"c":3}}
Right JSONB	{"a":1}	{"b":3}	{"b":{"c":3}}	{"b":{"c":4}}	{"b":{"c":4}}
Result		TRUE	FALSE	TRUE	FALSE

Key Moments - 3 Insights

Why does '{"a":1, "b":2}' @> '{"a":1}' return TRUE?

Because the left JSONB contains the key-value pair {"a":1} exactly, as shown in execution_table row 1.

Why does '{"a":1, "b":2}' @> '{"b":3}' return FALSE?

Because the value for key "b" in the left JSONB is 2, which does not match 3 in the right JSONB, as shown in execution_table row 2.

Does the operator check nested JSON objects?

Yes, it checks nested objects recursively, as shown in execution_table rows 3 and 4 where nested objects are compared.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result of checking '{"a":1, "b":2}' @> '{"a":1}'?

A NULL

B FALSE

C TRUE

D Error

💡 Hint

Refer to execution_table row 1 under the Result column.

At which step does the containment check return FALSE because of a value mismatch?

A Step 2

B Step 1

C Step 3

D Step 4

💡 Hint

Check execution_table rows where Result is FALSE and see the reason.

If the right JSONB is '{"b":{"c":3}}', what is the containment result when left JSONB is '{"a":1, "b":{"c":3}}'?

A FALSE

B TRUE

C NULL

D Error

💡 Hint

Look at execution_table row 3 for nested object containment.

Concept Snapshot

JSONB containment (@>) operator:
- Syntax: left_jsonb @> right_jsonb
- Returns TRUE if left contains right JSONB exactly
- Works recursively on nested JSON objects
- Useful for checking presence of key-value pairs
- Returns FALSE if any key or value mismatches

Full Transcript

The JSONB containment operator (@>) in PostgreSQL checks if the left JSONB value contains the right JSONB value. It returns TRUE if all key-value pairs in the right JSONB exist in the left JSONB, including nested objects. The execution steps show examples where the operator returns TRUE or FALSE based on matching keys and values. This operator is useful to filter JSONB data by presence of specific parts. The visual quiz tests understanding of containment results and nested checks.